.theory_section {
	/*height: 560px;*/
	height: 1000px;
	width: 100%;
}
.theory_title {
	font-size: 21px;
	height: 25px;
	line-height: 21px;
	color: #336;
	width: 100%;
	margin: 40px auto;
	text-align: center;

}
.theory_detail {
	background-image: url(./theory.png);
	width: 1000px;
	height: 550px;
}
.theory_content {
	font-size: 14px;
	color:#669;
	margin: 10px auto;
	width: 700px;
}